Rolled Material Research Articles

Analisa Risiko Keselamatan dan Kesehatan Kerja (K3) dengan Menggunakan Metode Hirarc di PT. Otomotif

Hazard Identification, Risk Assessment, and Control, or HIRARC, is a technique for detecting hazards that is used to calculate risk values and classify them into work-related hazards in order to define the risk control that is applied to each ongoing activity. The purpose of this study is to evaluate and control risks related to occupational safety and health hazards in the charging area of PT. Otomotif. This kind of study combines a descriptive methodology with a qualitative approach. The analysis conducted in the work area of PT. Otomotif's charging area revealed 38 possible dangers, which were categorized into four categories: Low Risk, Medium Risk, High Risk, and Extreme Risk. Controls carried out to reduce the possibility of work accidents include making conveyor bearing covers, making off charge alarms, replacing larger roller materials, adding APD Aprone longan and others.

Research Progress on Rolling Forming of Tungsten Alloy.

Tungsten is a metal with many unique characteristics, such as a high melting point, high hardness, high chemical stability, etc. It is widely used in high-end manufacturing, new energy, the defense industry, and other fields. However, tungsten also has room-temperature brittleness, recrystallization brittleness, and other shortcomings due to the adjustment of the composition and organizational structure, such as the addition of alloying elements, adjusting the phase ratio, the use of heat treatment and deformation strengthening, etc. Its performance can be improved to meet the requirements for use in different fields. At present, the main production method of tungsten alloy is powder metallurgy. The use of a rolling open billet rotary forging-stretching process can improve production efficiency and product quality, but in actual production, due to the combined effects of various factors, such as elastic deformation of rolling elements, plastic deformation of the rolled material, etc., the mechanical properties of tungsten plates and bars are often difficult to control effectively, seriously affecting rolling stability and production efficiency. For this reason, researchers have conducted extensive and deep research and optimization on the rolling process of tungsten alloys, including establishing mathematical models, performing numerical simulations, optimizing process parameters, etc., providing important references for the rolling and forming of tungsten alloys. Meanwhile, the material properties are greatly influenced by the microstructure, and the evolution of the microstructure can be well quantified by some advanced characterization techniques, such as SEM, TEM, EBSD, etc., so that certain properties of tungsten can be obtained by controlling the texture evolution. In conclusion, this paper comprehensively summarizes the research progress of tungsten alloy roll forming and provides an important reference for further improving the processing performance and production efficiency of tungsten alloy.

Comparison of high temperature oxidation behaviour of high speed steel and Hi-Cr steel

Abstract High speed steel and Hi-Cr steel are widely used as one of the important materials for rolls. The oxide layer during rolling plays a key role in the service life of the rolls and the quality of the rolled material. Therefore, it is very important to study the oxidation behaviour of high speed steel and Hi-Cr steel. In this paper, the oxidation behaviour of HSS and Hi-Cr steel is compared in the range of 500-700°C. The oxidation kinetic curve of HSS is dominated by a parabolic law, while the oxidation kinetic curve of Hi-Cr steel is dominated by a logarithmic law. To analyse the effect of their oxidation products on the oxidation behaviour, V2O5 in high speed steel plays a destructive role in the oxide layer, while Cr2O3 in Hi-Cr steel can effectively reduce the thickness of the oxide layer.

Electropolishing study of metastable austenitic steel AISI 347 for EBSD analyses

Abstract For the metastable austenitic steel AISI 347 (X6CrNiNb18-10), various electropolishing parameters were evaluated by means of hardness testing, electron backscatter diffraction (EBSD), and atomic force microscopy. Depending on the chosen parameters, different surface characteristics could be achieved simply by only varying voltage, flow rate, and polishing time, although EBSD indexing was always possible. Differences in hardness of up to 20 HV0.5 and in microscopic roughness could be detected on otherwise comparable samples. Finally, the microstructure distribution of a hot rolled bar material with a diameter of 153 mm made from AISI 347 was characterized over the cross section using the previously determined parameter set. Here, insights about recrystallization during forming were concluded and δ-ferrite was differentiated from α’-martensite by kernel average misorientation and morphology.

Technology for Protecting Building Envelopes in Construction Using Magnetron Sputtering

The global environmental agenda is aimed at saving energy resources in all areas of human activity. An important condition for energy saving and increasing energy efficiency is the thermal protection of buildings and structures of all types. Currently, when designing and constructing buildings, structurally oriented solutions are needed to provide conditions for the implementation of modern innovative technologies. At the same time, when producing new thermal insulation (heat-protective) materials, it is necessary to take into account such important issues as environmental friendliness and ensuring a comfortable microclimate. Issues of indoor air exchange are extremely important, especially during the spread of new viral infections. Thermal insulation (thermal protection) of buildings must ensure air circulation, that is, be vapor permeable. Polyester material has this property. Modern technologies make it possible to impart heat-reflecting properties to such materials by applying metallized nanolayers or their compounds to their surface. Among the methods for applying such layers, a special place is occupied by the magnetron sputtering method, which is used in the technology of applying protective coatings to the surface of products made from roll and sheet materials. With the development of applied technological research in the chemical industry, many substances (compounds) were invented, some of which gained such popularity that they began to be used in the production of a huge number of materials, including in the construction industry. One of these substances was polyester as a high-molecular compound, which became widely used in many areas of industry. Polyester material is often combined with other man-made or natural fibers. Among them: cotton, linen, wool, polyamide. As a result, we obtain a canvas (materials) with new characteristics, adding new unique properties, such as strength and wear resistance, does not fade in the sun, and does not require special care. Polyester fabric is used for suspended ceilings and in building materials. Its high density of 250 kg per cubic meter allows this to be done. By combining the production of polyester and cotton, the material acquires the properties of breathability, hygroscopicity and low thermal conductivity. The purpose of this article is to describe the technology of the ion-plasma processing method of combined linen materials with possible application in the construction industry.

Damage behavior of cold-rolled sintered fiber felts

Porous Materials, such as sintered fiber felts (SFFs), can contribute to the reduction of aircraft noise by acting as a low-noise trailing edge (TE). A rolling process with a time-varying rolling gap was sucessfully used to tailor the aeroacoustic properties of SFFs. To ensure the suitability of rolled porous materials for application, the mechanical properties after rolling must be investigated. The objective of this study was to clarify the effect of the rolling process on the damage evolution during tensile loading. A SFF consisting of a functional layer and a support grid made of alloy 1.4404 was used for rolling. Interrupted tensile tests in combination with computed tomography (CT) were used to investigate the damage evolution of as-received material, uniformly rolled material and material rolled with a gradient in thickness reduction. Metallographic examination and fracture surface analysis using scanning electron microscopy (SEM) complemented the CT analysis. Uniformly rolled material with a low degree of deformation (−0.74 ≤ φ < 0) failed identically to the as-received material. The functional layer failed first, starting from the center. The support grid subsequently failed due to the incremental failure of individual wires. The material rolled with a gradient in thickness reduction failed accordingly. A significant change in damage evolution occured for material rolled at high degrees of deformation φ ≤ −1.53, where the support grid fails first and the functional layer second. The rolling process using a time-varying rolling gap does not result in a detrimental mechanical behavior under tensile load. The results improve the general understanding of the effects of rolling processes on the properties of porous materials and allow the damage behavior to be taken into account with regard to its application as a TE.

Pengembangan Media Belajar Pendidikan Jasmani Materi Guling Depan Pada Mahasiswa Pendidikan Jasmani Semester III Universitas Muhammadiyah Mahakarya Aceh

The research titled "Development of Physical Education Learning Media for Forward Roll Material for Third Semester Physical Education Students at UMMAH" aims to produce interactive learning media in the form of a CD for forward roll material. This research uses a qualitative approach, with the population being all third-semester Physical Education students at UMMAH, totaling 26 students as the sample. Data collection techniques include observation and questionnaires. The research results show that: (1)Validation by material and media experts declared the media feasible to use without revision after three and two stages of evaluation, respectively. (2)Students stated that this learning media facilitates understanding and increases learning motivation. The appearance aspect is rated good and simple, while the quality of the text and video is considered easy to understand. The overall average rating of multimedia quality is "very good" with a score of 4.33.

Secondary use of recovered bitumen from waste roll materials

Secondary use of recovered bitumen from waste roll materials

Impact of hot rolling on the evolution of microstructure and mechanical properties of sintered commercially pure Ti compacts

While titanium (Ti) alloys offer significant advantages, such as high strength and corrosion resistance, their widespread utilization in various engineering sectors is hindered by their prohibitively high cost, which is attributed to expensive equipment and complex preparation processes. The present study centered on assessing the influence of multi-pass hot rolling, a commonly available industrial process, on the microstructure and mechanical properties of sintered powder metallurgy commercially pure Ti (cp-Ti). With increasing levels of accumulated deformation, the rolled materials exhibited a refined grain size, the formation of twins, and a reduced residual porosity, resulting in a tailored microstructure that enhanced the material's balance between strength and ductility. The ultimate tensile strength reached 574.8 MPa, with an elongation at break of 28.1%. The hardness peaked at 196.4 HV.

Effect of solution and artificial aging heat treatment on the hardness, friction and wear properties of laser cladding and roll-formed 18Ni300 materials

Abstract 18Ni300 is widely used in precision moulds, national defence, and other engineering fields due to its high strength and toughness, and because its properties can be greatly changed after heat treatment. In this research, the 18Ni300 cladding layer was fabricated on 18Ni300 substrate using the laser cladding method and a solid solution artificial aging treatment was carried out to analyse its macro morphology and metallographic organization. Comparison of hardness, friction, and wear of cladding layers manufactured by laser cladding and of materials produced by rolling was performed before and after heat treatment. The results show that the solution and artificial aging heat treatment has a significant effect on the microstructure of the cladding layer fabricated by laser cladding. There are obvious differences in the organization and morphology of different parts of the cladding layer before heat treatment; the metallographic organization and morphology of different parts of the cladding layer after heat treatment are the same. The trend of change of material hardness before and after heat treatment is the same in that the cladding layer is greater than the rolled material and the hardness of the material after heat treatment is much greater than the hardness of the material before heat treatment. The hardness and wear resistance of the material after solution and artificial aging heat treatment has been significantly improved, and the impact on the rolled production material of the melted cladding layer manufactured by laser cladding is even greater.

Correlative algorithm for determining the velocity of hot-rolled rod and wire using Cross-Section variations

Measuring the velocity of hot rod and wire during rolling is crucial for accurate control of rolling stands and blocks. To accomplish this, the velocity should be measured at strategically placed locations throughout the mill. The current state-of-the-art exhibits various techniques and methods for velocity measurement with their respective advantages and disadvantages, whereas measuring devices based on the Laser-Doppler principle are the most widely used.As part of the research and development of an eddy-current based cross-sectional area measurement, we observed variations in the cross-sectional area of rods and wires. These variations should be utilized for developing a correlative method for velocity measurement. Within the scope of this work, the implementation of a measuring system and the development of an algorithm is described. This algorithm has been applied to a real data set and evaluated, while also assessing the impact of influencing factors on the quality and accuracy of calculated rolled material velocity. Finally, it was successfully demonstrated that the developed solution approach works in practice and provides excellent results. Nevertheless, further validation is required and velocity determination needs to be compared with an independent reference to improve accuracy estimation.

Evaluating the joinability of thin-walled high pressure die cast aluminium for automotive structures using self-piercing rivets

This paper is the first to report successful application of self-pierce riveting (SPR) in thin-walled high pressure die cast (HPDC) aluminium for use in automotive applications. HPDC fabricated AA356x coupons were joined to conventional rolled RC5754 material. A set of industry-relevant joint stacks were created. Priority stacks included cast material as the upper layer. More challenging joints were also fabricated with cast material as the lower layer. Automotive industry key performance indicators were used to assess joint integrity. The key results and recommendations were:•HPDC aluminium was revealed to be able to be joined to rolled aluminium according to vehicle manufacturer automotive standards.•Process boundaries were established for satisfactory SPR joints across a range of material thicknesses and stack types.•SPR joint solutions were proven in the most challenging stacks with cast material as a bottom layer.•Greater variability in the joint key performance indicators was observed in stacks where the cast alloy is the top layer.•Microstructural analysis of both AA356x and RC5754 revealed differences in grain structure and hardness and it is proposed that this accounts for the increased variability.•Strength testing of lap shear joints demonstrated the mechanical effectiveness of an SPR joint including cast material. Under normal vehicle operating conditions, the performance of joints including cast material was equivalent to that of rolled material only joints. Following yielding, joints including cast material suffered a more brittle failure mode leading to differences in performance under crash scenarios.

مقاومة غمر التأكل عند الصقل بالخردق وتطبيق الاكسدة الدقيقة عند 0.5% من النيتروجين مع اضافة سبيكة الماغنيسيوم AZ31 Mg

The effect of shot peening (SP) and Micro Arc Oxidation (MAO) were utilized to characterize the performance of the corrosion resistance process at 0.5 % Nt with add AZ31 Mg alloy. Hot rolling at different rolling speeds has been investigated in this work. The surface of the rolling materials a rolling speed of 4.7 m/min and the rolling materials a rolling speed of 10 m/min were measured to create a clear definition of corrosion resistance physical properties. Experimental results show the surface of the rolling materials a rolling speed of 4.7 m/min had higher surface smoothness values than the one of the rolling at 10 m/min. It was observed that the corrosion rate changed in the first 24 of 168 hours. In the following hours, the corrosion rate showed different results according to the initial microstructure properties of the base materials. Initially, pore size was the dominant factor determining corrosion resistance, although, after coating the corrosion rate was affected by the twins formed, based on rolling speed, which enhanced the corrosion rate between 24 and 168 hours. Keyword: Shot peening; micro arc oxidation; AZ31; Nd; hot rolling; corrosion resistance.

Application of the PBL (Problem-Based Learning) Learning Model in Improving Front Roll Floor Gymnastics Ability at Class VII of SMPN 3 Gerung for the 2023-2024 academic year

The PBL Learning Model is a learning approach that is student-centered and focuses on problem solving. In the context of floor exercise abilities, especially the front roll sub-material. The approach used to improve front roll ability is Problem Based Learning (PBL). By using this approach, students are expected to be able to learn independently to find out good techniques through collaboration between their respective groups. So, from the overall process in this research, the total knowledge results were 2,060, the average knowledge was 79.2, the number of students who completed the study was 26, the percentage of students who completed was 100%, and the percentage of incomplete students was 0%. So, from the recapitulation data, the overall problem-based learning model for floor exercise on roll material has improved with the approach applied by teachers to students at SMPN 3 Gerung for the 2023-2024 academic year.

Pengaruh Massa Weight Roller terhadap Keausan Material dan Akselerasi Motor N-Max

The Nmax motorbike roller basically consists of 6 units which function to maintain and regulate motor acceleration found in the Roller Housing in the Continuously Variable Transmission (CVT) section which allows friction and wear to occur on the roller material. Acceleration is the level of acceleration that occurs in an object at a certain time, while material wear is the mechanical property of an object to accept loads, power and energy without causing damage. This research was carried out using a Tribometer test tool and logger pro analysis software. The results obtained show that material wear increases with increasing RPM. At 500 rpm, standard roller wear ranges from 0.107% to 0.346%, while at 1400 rpm, wear increases to range from 0.323% to 0.938%. The acceleration test results show that the standard roller with a mass of 13 grams has the lowest acceleration performance, with the lowest value occurring in test II at 1.26 m/s². Meanwhile, the 9 gram roller has the highest average acceleration of 4.82 m/s².

Zeta potential and activation energy effects in an EMHD non-Newtonian nanofluid flow over a wedge with Darcy-Forchheimer porous medium

The transmission of mass and heat alters the distinctive of non-Newtonian nanoliquid, which have several applications including extrusion, cooling of metallic plates, transport of biological fluids, coating, heat exchanger technology, and feed roll material movement. Mass and heat transfers in tangential hyperbolic nanoliquid streams via a wedge were analyzed, along with the roles played by Arrhenius activation and electro-magneto-hydrodynamics. Additionally, the impact of Darcy-Forchheimer flow and magnetic fields are considered in this simulation. By choosing suitable similarity variables, the necessary nonlinear partial differential formulation is transformed into nonlinear ODE’s (ordinary differential equations). After that, the equations are solved in Matlab through BVP4c solver. Flow fields, heat and mass transfer primary affecting factors were shown in graphically and discussed. Also, the coefficient of skin friction, Nusselt and Sherwood numbers are also presented graphically in the primary influenced parameters. An escalation in the Weissenberg number causes a decrease in the values of nanoliquids velocity, but an escalation in the power law index parameter causes an enhancement in nanoliquids velocity. If the suction and injection fluid have a zeta potential opposite that of the surface, it may improve interaction and change the boundary layer, thereby decreasing the coefficient of skin friction.

Experimental study on the surface defects of materials in bar rolling with a processing map applicable to billet-to-oval groove rolling

This paper proposes a systematic method for detecting surface defects (SDs) on specimens by performing a pilot hot (850°C–950°C) bar rolling test and suggests a processing map for billet-to-oval groove pass in bar rolling mills. Unlike previous studies, the specimens for the rolling test were prepared such that the billet surface became the surface of the specimens. A series of the rolling tests were performed at different temperature and area reduction ratios. Physical-chemical nondestructive testing was employed to detect SDs in the specimens before and after the rolling test. The depth of the SDs of the rolled specimens was measured using an optical microscope. The results revealed that the SDs depended both on the rolling parameters (temperature and reduction ratios) and the contact condition between the specimen and the roll groove during rolling, which is one of the characteristics of bar rolling that distinguishes it from flat rolling. The decrease in temperature caused an increase in the defect depth above the appropriate reduction ratio of 24.61% when the part of the specimen was in contact with the roll shoulder curve and the relief line of the oval roll groove. The proposed processing map presents a guiding path for operators in actual bar rolling mills to quickly determine a rolling condition (combination of temperature and reduction ratio), avoid SDs, and minimize defect depth within an acceptable range.

Enhanced thermal-mechanical properties of rolled tungsten bulk material reinforced by in situ nanosized Y–Zr–O particles

Tungsten is the most promising plasma facing material for fusion reactors. Rolled W–Y2(Zr)O3 bulk material has been successfully produced in this study for future fusion engineering applications. The introduction of Zr is conducive to the refinement of the second phase particles. Nano-sized Y–Zr–O particles are observed in the powder and bulk samples. Related results show that the Y–Zr–O particle dispersion distribution improves the heat load resistance of W–Y2(Zr)O3 composite material. For four-point bend experiments in the same sampling direction, the DBTT of W–Y2(Zr)O3 composite materials is lower compared to the pure tungsten. For the same material, the DBTT of the material was selected for testing along the RD direction is lower compared to the material was selected for testing along the TD direction. Findings of this study provide suggestions for the subsequent industrial preparation of nanoscale particle-doped tungsten materials.

The Microstructure and Magnetic Properties of a Soft Magnetic Fe-12Al Alloy Additively Manufactured via Laser Powder Bed Fusion (L-PBF)

Soft magnetic Fe-Al alloys have been a subject of research in the past. However, they never saw the same reception in technical applications as the Fe-Si or Fe-Ni alloys, which is, to some extent, due to a low ductility level and difficulties in manufacturing. Additive manufacturing (AM) technology could be a way to avoid issues in conventional manufacturing and produce soft magnetic components from these alloys, as has already been shown with similarly brittle Fe-Si alloys. While AM has already been applied to certain Fe-Al alloys, no magnetic properties of AM Fe-Al alloys have been reported in the literature so far. Therefore, in this work, a Fe-12Al alloy was additively manufactured through laser powder bed fusion (L-PBF) and characterized regarding its microstructure and magnetic properties. A comparison was made with the materials produced by casting and rolling, prepared from melts with an identical chemical composition. In order to improve the magnetic properties, a heat treatment at a higher temperature (1300 °C) than typically applied for conventionally manufactured materials (850–1150 °C) is proposed for the AM material. The specially heat-treated AM material reached values (HC: 11.3 A/m; µmax: 13.1 × 103) that were close to the heat-treated cast material (HC: 12.4 A/m; µmax: 20.3 × 103). While the DC magnetic values of hot- and cold-rolled materials (HC: 3.2 to 4.1 A/m; µmax: 36.6 to 40.4 × 103) were not met, the AM material actually showed fewer losses than the rolled material under AC conditions. One explanation for this effect can be domain refinement effects. This study shows that it is possible to additively manufacture Fe-Al alloys with good soft magnetic behavior. With optimized manufacturing and post-processing, further improvements of the magnetic properties of AM L-PBF Fe-12Al may still be possible.

Recrystallization of bulk nanostructured magnesium alloy AZ31 after severe plastic deformation: an in situ diffraction study

The magnesium alloy AZ31, which has undergone high-pressure torsion processing, was subjected to in situ annealing microbeam synchrotron high-energy X-ray diffraction and compared to the as-received rolled sheet material that was investigated through in situ neutron diffraction. While the latter only exhibits thermal expansion and minor recovery, the nanostructured specimen displays a complex evolution, including recovery, strong recrystallization, phase transformations, and various regimes of grain growth. Nanometer-scale grain sizes, determined using Williamson–Hall analysis, exhibit seamless growth, aligning with the transition to larger grains, as assessed through the occupancy of single-grain reflections on the diffraction rings. The study uncovers strain anomalies resulting from thermal expansion, segregation of Al atoms, and the kinetics of vacancy creation and annihilation. Notably, a substantial number of excess vacancies were generated through high-pressure torsion and maintained for driving the recrystallization and forming highly activated volumes for diffusion and phase precipitation during heating. The unsystematic scatter observed in the Williamson–Hall plot indicates high dislocation densities following severe plastic deformation, which significantly decrease during recrystallization. Subsequently, dislocations reappear during grain growth, likely in response to torque gradients in larger grains. It is worth noting that the characteristics of unsystematic scatter differ for dislocations created at high and low temperatures, underscoring the strong temperature dependence of slip system activation.Graphical